Improvement in steasvi-engines



. 4 .h --Sh H. DAVEY- S eets eetl Steam-Engine. No, 167,509, 7 PatentedSept.7,1875.

N. PEERS. PHOTO-LITNOERAFHER, WASHINGTON. D c.

4 Sheets--Sheet 2. H. DAVEY.

, Steam-Engine, N0.l67,509 PatentedSept.7,l875.

4 Sheets--Sheet 3 H. DAVEY. Steam-Engine:

No, 167,509, Patented Sept.'7,1875.

HENEY DAVEY, or

IMPROVEMENT IN Specification forming part of Letters Patent No. 167,509,dated September 7, 1875;

LEEDS, ENGLAND.

STEAM-ENGINES.

application .filed August 1, 1874.

To all whom it may concern:

Be it known that I, HENRY DAVEY, of Leeds, in the county of York,England, have. invented an Improved Method of Working the Slides ofSteam-Engines and later-Pressure Engines, and do hereby declare that thefollowing description, taken in connection with the accompanyingdrawings, hereinafter referred to, forms a full and exact specificationof the same, wherein I have set forth the nature and principles of mysaid improvement, by which my invention may be distinguished from othersof a similar class, together with such parts as I claim and desire tosecure by Letters Patentthat is to say:

This invention relates to a method of working the slides of steam orwater pressure engines, without the use of eccentrics, cams, or otherrotating parts, the movement of the main piston being employed to movethe main slide through a part of its stroke, and also to move the slideof a subsidiary cylinder, and the rest of the stroke of the main slidebeing efl'ected by the movement of the piston of the said subsidiarycylinder. The speed with which the stroke of the main slide is completed or effected is governed by a cataract-that is, the resistance ofa liquid in a cylinder to a piston moving therein. This mode of workingthe slide, although peculiarly applicable to direet-acting engines, suchas are employed to work pumps without connecting-rods, cranks, orfly-wheels, is applicable also to engines working rotating shafts, andeither to simple or compound engines, and either in combination with orwithout expansion Valves or slides.

In order that my improvement may be the better understood, I will referto the accompanying drawings, and to the figures and letters markedthereon. These drawings represent several modified forms in which myinvention may be carried into practical effect, the same letters beingemployed in the several figures to indicate corresponding parts of theapparatus.

The figures on Sheets 1, II, III, and IV represent a form of theapparatus adapted to work the slides of a compound pumping-engine,having a high-pressure and a low-pressure cylinder, with means ofeffecting a pause at the termination of each stroke of the engine, andof working a double-beat expansion-valve for the high-pressure cylinder.In those sheets Figure 1 represents a side view, and Fig. 2 a plan ofthe two cylinders with the adjacent parts. Fig. 3 is a longitudinalsection through the slides of the two cylinders. Fig. 4 is a plan of thetwo slide-levers and their connections, the subsidiary cylinder and itsslide, and the cataract-cylinder, being shown in sectional plan. Fig. 5is a transverse section through the subsidiary cylinder and Fig. 6 is atransverse section through the cataract-cylinder. The Figs. at to 6,inclusive, are drawn to an enlarged scale.

The piston-rod P of the front or high-pressure cylinder G, and the twopiston-rods P of the hinder or lowpressure cylinder G are secured to onecross-head, 0, connected by connecting-rods O to the levers for workingthe pump -rods. An arm, .projecting down from the cross-head O, isconnected by a rod, N, to a long arm, N of arocking shaft, N, mounted inbearings on the framing of the engine. A short arm, N on this rockingshaft is connected by a rod, L, to the end E of a I pair of horizontalleversQE, which have their common fulcrum at E on a rod, 0 connectingthe piston (J of the subsidiary cylinder 0 with the piston M of thecataract-cylinder M At E about the middle of the levers E, they arejointed to the rod A which connects the steam-slides A and K of the twocylinders G and G. A'pin, E secured in the levers E, is connected byalink, H to the end H of a lever, H,-having its fulcrum at H which iscapable of being moved by means of a worm, as will hereafter bedescribed; but which fulcrum may be considered as being stationaryduring the ordinary working of the engine. The lever B is connected at Htofthe rod B of the slide B, commanding the ports of the subsidiarycylinder G L It will be seen that the connections from the cross-head Oto the lever E are such that the end E of the latter is made to move intime with the former and'with the main pistons, but always in theopposite direction, and through a considerably shorter stroke. As thepistons make their outstroke or toward the left, the lever E is causedto oscillate toward the right hand. The secondary lever H is thus causedalso to oscillate toward the right, drawing the slide 13 in the samedirection, so as to uncover the left-hand port of admission to thesubsidiary cylinder 0. Steam then enters this cylinder from the jacket Aand, pressing on the piston O, propels it toward the right with a speedwhich is controlled by the resistance offered to the piston M by theliquid in the cataractcylinder M This resistance is regulated byadjusting a screwplug, M so as to interrupt more or less the passage Mfrom the one end of the cylinder M to the other. The movement of thepiston O, carrying the end E of the lever E toward the right, causes themiddle E of that lever also to move toward the right, and thus theslides A and K are moved so as to admit steam to the left-hand ends ofthe main cylinders G and G. The pistons of those cylinders being nowpropelled backward, the lever E is caused to oscillate toward the left,moving the slide B in that direction, whereby the piston O is caused tomake its back-stroke, shifting the points E and E toward the left, andmoving back the slides A and K. In order to work the high-pressurecylinder G expansively, a double-beat valve, 1, in the steam supply ofthe jacket A is worked in accord with the movement of the slide in thefollowing manner: The slide-rod A prolonged through a stuffing-boxbeyond the front of the slidejacket, works a lever, B, having two arms,R and R which have pins working in slots P of two oblique rods, P. Theserods are jointed to one arm of a lever, Q, the other arm of which isjointed to the rod of the valve I. When the slide A'is moved, as abovedescribed, either to the right or to the left, the pin of R or of Rbeing brought to bear on the lower end of the slot P in which it isengaged, draws down the rods P, and thereby causes, the valve I to beraised for the admission of steam to the jacket A. When, however, by theretreat of the slide A, effected by the backward movement of the lever Eduring the stroke of the main pistons, the pin of R or of R is made torise, the valve I closes and cuts off the steam supply. The length ofthe rods P can be adjusted by screw-handles P so as" to regulate thelift of the valve I. An eccentric lever, Q, mounted on the valve-rod canbe turned up by hand, so as to render the stroke of the lever Qinefiective for raising the valve I, and the valve in that caseremaining closed, the engine is stopped.

Having thus described the nature of my invention, and the best means Iknow of carrying the same into practical effect, I claim 1. Thecombination, with the main valverod of the lever E, one end of which isconnected by intermediate mechanism with the main piston, and the otherend with the piston-rod of the subsidiary cylinder, substantially as andfor the purposes described.

2. The combination of the lever E, connected to the main piston, the rodpiston O, valve B, lever H, link H and the cataractcylindersubstantially as and for the purpose described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses this 20th day of June, 1874.

HENRY DAVEY.

Witnesses:

THos. E. ORocKER, JONATHAN DAVEY.

